The Mole Attack (Day 9, Midday)

[Beside the Zombie Dungeon: the Siege Fort]

"Well, well, if it isn't the Director of Books-dono."

Atop a tower fused into the rampart on the north face of the siege fort, the Band Commander Kishi Harima-no-suke came out to greet her.

"The situation is… one look and it's plain enough. Still, there certainly are a great many headless dead."

"Yes, more than ten thousand, by our reckoning. They seem to have some small measure of wit; provoke them, and they won't come at us. Now and then one gets pushed out and stumbles over here, though."

"Without further ado, we'll settle this before the day is out."

"Oh-ho. Surely you don't mean to drop the whole dungeon into a pitfall. It lies outside our range, and there are no pit-digging brats about, so we can't very well dig directly beneath the enemy dungeon, but."

"That 'surely' is exactly what I'm considering. First, beneath the flat ground where the Panjandrum runs about, we absorb the soil from the eastern face alone and open up a deep cavity. Then we pour vast quantities of water underground to scour away the soil beneath the enemy dungeon. By absorbing the muddy water and returning only the clean water, we dig clean through the dungeon's underside, and it caves in under its own weight. Since the soil on the western face remains, though, the dungeon slides down toward the east, that is, toward our sphere of influence. A dungeon structure collapses once it leaves its sphere of influence, so any portion that slides in beneath ours should crumble away in turn."

"Should?"

"It isn't a hundred percent. So please have everyone evacuate from the eastern face. When a dungeon body is pitted against a mere sphere of influence, there's a chance the body (the Kozukappara Execution Ground itself) proves the stronger, and it's our own western portion that collapses instead. But a considerable stretch of the western side lies within our sphere of influence, so should that happen, we simply dig the ground deeper still, tilt the whole enemy dungeon over, topple it, drop the zombies, and deal with them then."

"And how deep would that need to be?"

"The enemy's thickness is at most a few meters (one or two jō, I'd estimate), but its breadth is some thirty ken, so if we dig something like sixteen or seventeen jō, it ought to slide down."

"Director of Books-dono, twenty-seven ken is an outrageous depth. An ordinary well is twenty ken at most."

"Since we mean to dig away an entire dungeon, this much labor is necessary. With the method of sending in ordinary adventurers to capture it, the projected casualties are far too great."

"True enough. With that many headless dead, it would never go off with everyone unharmed."

"There are cases that call for a do-or-die squad willing to brave danger, but producing casualties that way is no fitting method for the Library-City Dungeon."

Marie had the officers and soldiers on the eastern wall evacuated, ordering some of them to fall back as far as Toda Village where Rāja was and to rest, and then, using the dungeon's function, she steadily removed earth and sand to carve out a cavity. Once the cavity had reached a certain size, she poured in the water drawn from the distant core, digging clean through the ground beneath the Zombie Dungeon. As the underground collapsed, the ground trembled faintly.

"Director of Books-dono, the water, you draw it from afar?"

"Even at the edge of the dungeon's sphere of influence, we can convert sand and the like that's already there into dungeon structures, and we can summon duplicates of the library buildings, but water and electricity, that is, the power that drives the dungeon, must be supplied from the core. If there's moisture in the air, we could also have Vasanti make it rain, though."

"I see. So it isn't all just as you please."

"Indeed. If the east (the left side) sinks even slightly, please let me know. At that point I'll increase the water all at once and bring it down. As for the night heron, Goi Kurōdo-san, once I give the signal, aerial reconnaissance, please. On the western side the dungeon's sphere of influence is narrow, and on the eastern side there's a danger of straying out of the sphere when the dungeons collide, so circle in the sky to the north."